Canon A-1 Repair Manual page 123

4. CLK (l4P)
Clock Pulse Input from OSC/lnterface IC .
CLK)
(See 3.3.15
5. SYNC (07) (15P)
System Trigger Input from Decoder Driver IC (3.3.14 07)
6.
VADJ (16P)
This pin has no external connection. Internally it is
connected to the voltage divider on the low voltage
interlock comparator.
7. BCK (17P)
EI Vc
'-----1+
CP
VAOJ-t---+_/
>--LvDET
LvDET
Fig. 3-6
Battery Checker Circuit and Clear circuit. During
normal operation El is present at pin 17. When the
battery check switch is closed, it is grounded.
Note: Circuit clear takes place when button is pressed,
but since battery check actually energizes Mgl
and Mg3 the outward signs of clear are not
apparent until the button is released.
8. TP (18P)
Temperature compensation circuit Output (approx. O.6V)
9 . EV 18 (19P)
Normally the same voltage as EV 18 MOS OUT is
-- Part of temperature compensation circuit .
voltage is same as VC'
=
1 . 219 ± 38 mY) .
present.
(Normally